I don't like coats, they're bulky and get in my way and I'll only wear them in extreme/long time outside times.

Do you all drive? I'd just have the heat in the car (like in the house) keep you warm? I cleaned the car this morning with no coat and it was 16 my car thermometer said. It takes awhile for the heater to warm the car but maybe you can go out, turn on the car and heat and go back in the house and wait 5 minutes before going and getting in the car?

Can you buy her a muff or hat or gloves? Most of the heat in our bodies goes out our extremities, especially our head, then hands and feet. I think she might like a muff? Little girls like muffs (I still remember mine from the mid-1950's; rabbit's fur lined with silk).